The antigenic determinants of lysozyme will be delineated. Lysozyme will be cleaved enzymically and chemically to yield fragments with intact disulfide bonds. The peptides will be tested for their inhibitory activity of lysozyme-antilysozyme system. Immunochemically active peptides will be purified, characterized and studied for their binding by equilibrium dialysis. Antibodies against pure peptides will be prepared and studied for their inhibition of enzymic activity of lysozyme. The relative amount of antibodies against the different antigenic determinants in sera of a given animal at different times during immunization and in different animals will be quantitated. This will shed some light on the antigenic determinants in terms of their relative immunodominancy. Also the immunochemistry of lysozyme derivatives will be studied, which are chemically modified at amino acid sites that have not yet been investigated. Conformational alterations resulting from the modification will be determined.